1. Field of the Invention
The present invention relates generally to magnetic recording/playback apparatus, and more particularly, to an improved flexible disc drive including an elongated frame pivotally mounted to a housing and disposed over a drive spindle, and an elongated spring member depending from the frame for carrying a spindle-clamping assembly in such a manner as to move it into or out of a clamping relationship with the spindle.
2. Description of the Prior Art
A flexible disc recording medium, sometimes called a floppy-disc or diskette cartridge, is a mylar disc enclosed in a plastic envelope having apertures for enabling the disc to be driven. Magnetic material is secured to the faces of the disc so as to provide the recording surfaces. A flexible disc drive for receiving and making functional use of the cartridge typically consists of a drive mechanism, a read/write head, a track positioning mechanism and means for receiving and loading the cartridge onto the drive mechanism and the read/write head.
In view of the relatively low cost of the diskette cartridges and the capability of the disc drives to randomly access information stored on the disc such devices have been employed in the data processing industry as a micro code back-up, a diagnostic aid, an error logger, and for initially loading a control program for computers and storage control systems. However, flexible disc drives have not been accepted as an information storage device by the word processing industry because of the large size and storage capacities of the flexible discs (i.e. about 500,000 bytes/disc) and the relatively large size and high cost of the disc drive relative to that of magnetic tape cassettes and magnetic card typewriters. For example, magnetic cards generally are capable of storing about 5,000 bytes which corresponds to about one page of typewritten information.
In a prior art flexible magnetic disc drive apparatus of the type used in the data processing industry a rigid disc positioner having a flanged head and a truncated cone-shaped lead surface is mounted to a door of the apparatus. The positioner is capable of being actuated such that the lead surface passes through the central opening of a magnetic disc and into a recess in a drive spindle. Further movement of the positioner stretches the disc opening and slides the disc toward the flanged head of the positioner so as to clamp the disc to the front surface of the spindle. In such a device, a slight annular spacing occurs between the outer surface of the positioner and the wall defining the recess in the spindle which tends to cause a misregistration of the disc upon the spindle and hence, a corresponding eccentricity in scribing the tracks of the disc. In addition, it has been found that when the door is closed with the cartridge slightly misregistered, the disc may be damaged. As previously mentioned such a device is too large and too expensive for use in the word processing industry.
Another prior art device utilizes a cartridge guide to direct the cartridge during its insertion toward the spindle. Such a device typically employs a door fixed to the cartridge guide by means of cams or linkages so that when the door is closed the cartridge is moved into registration with the drive spindle.
In yet another prior art device an apparatus for clamping and centering a flexible magnetic disc is provided which includes a spindle-clamping assembly that is mounted to the door of the device and which utilizes a helical clamp spring to force the clamping assembly into the spindle when the door is closed. However, such clamp springs occupy a relatively large space in the device and consequently cannot be utilized in disc drives having a physically smaller size.
Examples of prior art devices are found in U.S. Pat. No. 3,678,481, entitled "Data Storage Apparatus Employing A Single Magnetic Disk," by Warren L. Dalziel, Jay B. Nilson and Donald L. Wortner; U.S. Pat. No. 3,609,722, entitled "Center Sealing Data Disk Cassette and Processing Machine," to George E. Zenzefilis; and U.S. Pat. No. 3,768,815, entitled "Apparatus For Clamping And Centering A Flexible Magnetic Disk," by Edward L. Mathurin.